Method for fixing one or more previously twisted or coiled yarns or the like during unwinding thereof, particularly applicable to alteration of textureized yarn



y 1968 M. RATTI METHOD FOR FIXING ONE OR MORE PREVIOUSLY TWISTED OR COILED YARNS OR THE LIKE DURING UNWINDING THEREOF, PARTICULARLY APPLICABLE TO ALTERATION OF TEXTURIZED YARN Flled Sept 24 1965 INVENTOR HIC HELE PATT I KM W v sau'r United States Patent 3,383,850 METHOD FGR FIXING ONE OR MGRE PREVIOUS- LY TWTSTED 0R CGTLED YARNS GR THE LlKE DURING UNWINDHNG THEREQF, PARTICULAR- LY APPL1ABLE T0 ALTERATEGN OF TEXTUR- IZED YARN Michele Ratti, Luino, Varese, Italy Filed Sept. 24, 1965, Ser. No. 489,896 Claims priority, application italy, Aug. 6, 1%5, 7,853/ 65 2 Claims. (Cl. 57-157) ABSTRACT OF THE DISCLOSURE Yarn is twisted and the twisted yarn is passed through a heating chamber by feed rolls at the entrance and exit of the chamber which hold the yarn in a straight path and out of contact with solid hot surfaces while being heated. The yarn is heat-set thereby in the original twisted condition, and may be wound on bobbins and otherwise processed thereafter.

The present invention relates to a method for setting a yarn at a desired tension during the unwinding and winding thereof.

The method is characterized in that the yarn, after unwinding from twisting or coiling members, passes between two spaced pairs of driven rollers rotating at dilferent speeds to provide a controlled overor under-supply of yarn on the straight path between the two pairs of rollers wherein the yarn is heated without any direct contact with hot solid surfaces. 7

For a better understanding of the invention, the accompanying drawing shows apparatus for performing the method of the invention as applied to elasticized or texturized synthetic fibres.

FIGURE 1 shows a first apparatus of the invention in a perspective view and partly in section.

FIGURE 2 is an axial cross-section of a spool from which yarn is unwound in the apparatus of FIG. 1 under uniform tension and with the desired twist.

FIGURE 3 shows a modified device for producing the initial twist in the apparatus of FIG. 1.

FIGURE 4 shows a further modification similar to that of FIG. 3.

The apparatus shown in FIG. 1 comprises a spool 1 from which yarn is unwound while simultaneously being given a twist about its longitudinal axis under uniform tension.

The twisting operation causes a helicoidal arrangement of the fibres in the elasticized or texturized yarn that allows the yarn to vary its length without relative displacement of the fibres thereof, as would occur with fibres parallel to the direction of yarn elongation.

The yarn 2 is led by a thread guide 3 into the nip of a first pair of driven feed rolls 4-4, and is drawn from the first pair in a Straight path by a second pair of feed rolls 5-5 placed at a distance AB from the rolls 4-4.

The pairs of feed rolls 4 4' and 55 rotate at different surface speeds, to provide the desired overor under-supply of yarn on the straight length A-B.

The yarn is set while moving in the straight length A-B by being heated within a hot air chamber 8 at a uniform temperature.

The yarn is not in frictional contact with any hot solid i-atented lsiay 21, 1963 surface along the heating path A-B, but is merely hit by hot air or an infrared ray beam which does not change the shape of the yarn and does not disturb its fibre arrange ment. From the feed rollers 5-5 the yarn passes over a lubricating roller 6 and is wound on spools 7, ready for the next operation.

FIGURE 2 is an axial section of the spool 1 from which the yarn is unwound in a twisting step at very uniform tension.

It has an upper flange 1' whose diameter is smaller than that of the lower flange 1".

its core tapers in diameter from the flange 1 toward the fiange 1" so that layers 9 of the wound yarn slip from the spool at a uniform rate.

Thus, a balloon is formed in the yarn 2v which draws the yarn from the spool 1 with a uniform force from whichever point the yarn is unwound.

FIGURE 3 illustrates a twisting assembly which may replace the spool 1 in the apparatus of FIG. 1.

It has a stationary bobbin 9, from which thread 10 slips axially upwardly through tension members 11 from which it is downwardly directed to enter the bottom of the hollow spindle 13 of a rotating bobbin 14. A second thread 15 unwinds upwardly from the bobbin 14 and is twisted at a guide 16 with the thread 10.

In the modified arrangement shown in FIG. 4, a thread 10 unwinding from a stationary bobbin 9 is an upwardly axial direction through a tension member 11 passes to the rotating bellow spindle 17 of a bobbin 14 where it is joined by the thread 15 of the bobbin 14 which is unwound axially upward and passes through the spindle 17 from top to bottom.

A twisted and balanced yarn 19 is obtained and then passes through the feed rollers 4-4 and 55'.

What is claimed is:

1. A method of treating heat-settable yarn which comprises:

(a) twisting said yarn about the longitudinal axis there- (b) passing the twisted yarn through the nip between the rollers of a first pair of feed rollers;

(c) drawing said yarn from said nip in a straight path by means of a second pair of feed rollers rotating at a surface speed different from the surface speed of said first pair While keeping said yarn spaced from all solid surfaces while in said straight path; and

(d) heating the yarn while in said path to a temperature sufficient to set the same.

2. A method as set forth in claim 1, wherein said first mentioned yarn is being twisted about a second yarn prior to passage through said nip, and is passed through said nip and drawn from said nip over said path jointly with said second yarn.

References Gited UNITED STATES PATENTS 2,993,333 7/1961 Bergh et al 2862 XR 1,010,354 11/1911 Dustin 242l18.3 1,652,601 12/1927 Blair 242-1183 2,295,222 9/ 1942 Krent-ler 242-1183 2,105,474 1/1938 Dickie et al 5735 3,162,995 12/1964 Comer et al 57--157 FRANK I. COHEN, Primary Examiner.

DONALD WATKINS, Assistant Examiner. 

